Method of preparation of dental prosthetic devices



March 30, 1954 0. s. MCPHEE NTAL PROSTHETIC DEVICES a METHOD OF PREPARATION OF DE.

2 Sheets-Sheet l F'iled March 27, 1951 Duucm s. MC PHEE lll'l'l... n

(Ittornegs March 30, 19 54 5 McPHEE 2,673,397

METHOD OF PREPARATION OF DENTAL PROSTHETIC DEVICES Filed March 27, 1951 2 Sheets-Sheet 2 DUNCAN MO PHEE Jnnentor Gttornegs Patented Mar. 30, 1954 UNITED STATES PATENT OFFICE METHOD OF PREPARATION OF DENTAL PROSTHETIC DEVICES 6 Claims. 1

My invention relates to an improved method of preparation of dental prosthetic devices and, more particularly, relates to a method of determining the inclination of a patients plane of occlusion relative the horizontal and of establishing that inclination in the models when they are positioned in an articulator.

This application is a continuation in part of my application, Serial No. 148,128, filed March 7, 1950, now Patent No. 2,621,406.

In the preparation of dental prosthetic devices that are fully useful, life-like, pleasing and comfortable to the patient, and which function properly in the mouth of the patient, it is necessary that the dentist know as much as possible about the characteristics of the patients jaw. While much can be determined from observation, many of the particular characteristics areblurred or indeterminable when the patients natural teeth have been extracted. Then the maxilla and mandible have a relation that is largely one of irregular space therebetween and often the actual frontal dimensions lost or indeterminable by conventional methods. Such conditions particularly complicate the establishment in an articulator of the models of the upper and lower jaws that are normally formed according to conventional practices. I have found that if the lateral inclination, if any, that exists in the maxilla relative the horizontal can be accurately determined by means of a bite-plate in the mouth, such lateral incline tion can be established in the articulator with considerable speed and a very high degree of accuracy. Having established the location or aspect of the maxilla model, it becomes very simple thereafter to establish in the articulator, the corresponding aspect of the mandible relative the maxilla in the relation thereto found in the patients mouth. Then, according to other improved techniques that I have developed, the dentist may proceed with confidence that he will simply and accurately prepare dentures which will be comfortable and will function properly when applied to the mouth. In fact, such success has been enjoyed with the process disclosed that seldom, if ever, is it necessary to perform any more than the slightest of post-fitting adjustments between dentures or with regard to their fit on the jaws in the relief of undesirable or harmful pressures.

Among the important objects of my invention,

therefore, is to provide a simple and accurate method of determining lateral inclinations of a patients jaw in. such manner that such deter mination can be readily reproduced in an articulator as an aid in the mounting of the models in faithful correspondence to nature and to add to the comfort and suitability of the dentures for mastication and aesthetic purposes; to pro- Vide a process for producing an accurate determination of maxilla aspect, through use of a maxilla bite-plate, and for transferring that aspect into an articulator; and to devise a method of adjusting the models in an articulator to obtain a proper division of the intermaxillary space while providing a desirable plane of occlusion, whereby dentures produced will properly distribute the grinding pressures of mastication to favor or disfavor bone conditions found in the jaws of the patient.

It will be apparent that these objects are of a general nature and it is pointed out that these and other objects will be more apparent from reading the following description specifying the techniques and apparatus employed in carrying out my process, reference being made to the accompanying drawings showing a specific embodiment of apparatus adapted for use in the preparation of dentures by my method. It is to be understood, however that certain variations in the method described may be made by those skilled in the art without departing from the scope of the invention as exemplified by the accompanying claims.

In the drawings:

Figure 1 is a side view of a Fournet type articulator including certain appliances which I have developed and showing a maxilla bite-plate and model positioned on a bite-table;

Figure 2 is a side view of the articulator with portions broken away for convenience of illustration and showing upper and lower models and bite-plates in position therein;

Figure 3 is a perspective view of the bite-table and bite-plate showing in detail the bite-table levelling means;

Figure 4 is a perspective view of the spiling means employed in scribing a line on a model; and

Figure 5 is an enlarged perspective view, in exploded and fragmentary form, showing the bite-table and its supporting assembly.

Preparation of bite plates In the practice of my invention, I employ the customary techniques in the preparation of upper bite-plate I 0 and lower bite-plate i 2 which fit models of the maxilla and mandible of the patient, I 4 and I6 respectively. As is well known to those skilled in the art. a pl s ic em impression is first taken of the patients jaw; and

from this is molded, by casting therein, plaster models of upper and lower jaws, as M and [6, on which the denture will be constructed. Following the preparation of models l4, I6, bite-plates H), 12 are molded in conventional manner in the models. The interior recesses of bite-plates l6, l2 accurately fit the patients jaw and may be placed thereon as desired by the dentist, for example as in applying line H (Figure 3) which corresponds to the median line of the face. I prefer to form the lower portions of the bite-plate with a substantially broad, flat surface, as H in Figure 3, in order that it may be mounted securely on bite-table [8, to which it is secured with line H coinciding with fore-and-aft median IQ of the bite-table. The bite-plate is secured to the bite-table by the application of wax adhesive 20 shown in Figure 3.

The bite table and supporting assembly In the determination of the lateral aspect of the patients jaw relative horizontal, upper biteplate It is secured to bite-table l8, as shown in Figure 3 with median lines l1 and I9 coinciding. Upper bite-plate it is placed in the patients mouth with the bite-plate firmly seated on the maxilla. At that time, arm 22 will extend forwardly of the mouth between the patients lips. On arm 22 is lateral arm 24 which provides the support for spirit level 28 that is rockably mounted on the generally horizontal screw pivot 28. It will be noted that by this arrangement spirit level 26 is arranged to rock in an upright plane that is parallel to a similar upright plane passing laterally through the patients jaw. With the patients head in a vertical position, whenever the spirit level is located in that plane and oriented so that the bubble is centered in the tube, a determination of the aspect of the patients jaw laterally with respect to the horizontal will be established. When the bite-table and biteplate are removed from the mouth and subsequently mounted on a support and the spirit level is again placed with the bubble centered, biteplate In will be located laterally in exactly the same position with relation to the horizontal that it occupied in the mouth.

For convenience of operation in the leveling of spirit level 25 and in order to maintain relative adjustments of spirit level 25 to bite-table .7

[8 during such transfer and mounting, I provide manually operable adjusting and securing means between the spirit level and supporting arm 22 of the bite-table. The means is shown in Figure 3 and comprises bearing block 30 in which is rotatably mounted pin 32 having knurled knob 34 and screw shank 36 on which moves traveler nut 38. Pin 2 can rotate but can not move longitudinally in block 30; and, as it is rotated, it will cause nut 38 to move in whichever direction is dictated by the lead of the threads and the direction of rotation. A semi-rigid small rod or wire link 49 is connected between nut 38 and spirit level 26. By forming link 48 as a U-shaped loop and by properly selecting material of suitable resiliency, I can arrange that the rotation of screw 38 will accurately be translated into movement of nut 38 and a correlative tilting or rocking of the spirit level. In addition, the resiliency of U-shaped link 40 is such that at all times the link is tensioned to such a degree that any slack between the screw and nut threads is absorbed and. lost motion is precluded. This makes it possible to avoid error during the transfer of a predetermined arrangement of the level from the patients of the top of bite'table I8.

4 mouth to a supporting device such as an articulator.

A supporting assembly for bite-table [8, such as could be used to mount it in an articulator or the like, is shown in Figures 1 and 5. This assembly is used to support the bite-table and to adjust the same to the plane it assumed in the patients jaw by tilting the bite-table until spirit level 26 has the same reading. The center of bite-table I8 is bored to provide opening 42 which is encircled by interiorly threaded collar 44 on the under side of the table. This is for the purpose of detachably mounting the bite-table on a supporting column which may be supported by an articulator. The bite-table should be rockable on column 45. An exteriorly threaded stud 48 is positioned in opening 42 and has a bifurcated lower end that straddles fin 49 which is part of the column. A pivot pin 5!! hingedly joins the stud to the column so that it may be rocked thereon. The length of the stud and the location of the pivot pin is such that, when the stud is properly joined to bite-table l8 by being threaded therein, the axis of pivot pin 50 coincides with median is and lies in the plane This arrangement insures that when bite-table I8 is rocked the surface of the table will always coincide with the axis about which rocking takes place. Thus, with the center of the table positioned over the center of support column 46 and under the center of an upper support of an articulator, even though the bite-table is rocked the bite-plate will not be moved laterally away from its central position in the articulator.

Rocking of stud 48 on column 46 is obtained by means of moving lever arm 54 which is pivotally connected to stud 48 at one end. In the lower position of the column is journaled screw 56 having knob 58 and on which screw is moved traveler nut 60. Horn 62 on nut extends upward and is pivotally connected to the other end of lever 54. Screw 56 is journaled in column 46 in a manner permitt ng rotary movement but not permitting longitudinal movement, so rotary movement of knob 58 is translated into longitudinal movement of traveler nut 69 and corresponding tilting of bite-table l8 through horn 82 and lever arm 54.

After spirit level 26 has been adjusted to a horizontal position while bite-plate it was positioned snugly on the patients maxilla, bite-table I8 is positioned on column 46 and is tilted by means of adjustment of knob 58 until spirit level 26 again is in a horizontal position. At this point bite-plate It has the same lateral inclination regarding the horizontal as it assumed while in engagement with the patients maxilla.

Articulator and associated parts In the preparation of dentures according to my method, I prefer to use a Fournet-type articulator such as is shown in Figures 1 and 2. This articulator has a T-shaped base with a forwardly extending arm 10 and rearwardly located lateral arms. as H. Foot 13 on front arm 10 has a vertical passage 15 for the reception of various appliances and thumb screw 14 intersects passage 15 to clamp the stems of appliances that may be therein inserted. The lateral arms, as H, each have adjustable feet, as 83, which may be employed in leveling the articulator on a table or bench. As will be more apparent later, the articulator should be leveled so that column 46 will be truly vertical.

Rsing from the juncture of arms 16, H is pillar 16 having a capping boss 11 on its upper end.-

Upper arm is-bifurcated tostraddleboss- 11: thereto by pin 19; Leg" the reception of mounting pins on appliances used in connection with the artioulator. Such an appliance is shown in Figures 1 and 2 in which there is an upper mounting plate. comprising Shaft 88. hinge leaf 89 securedthereto at right angles, and h nged mounting plate'90 pivotally connected to hinge leaf 89 by pin 92 Mounting plate 90 has ports, not shown, for reception of plaster Whena model is mounted-thereon.

By placing the upper: mounting p ate inv the articulator gudgeon 84 bubb e level with its shaft locked in place in by screw ilfiand attaching *n versal 94 on the upper end of shaft 88-. it is possible through manipulation of the-adjustable feet. as 03, to place the articulator in oriented positionwith passage 85 directly overlyin pas-- sage 15. In this leveled adiustrnent. app iances placed in arms 1IIand 18 wil be accurately superimposed. Universal'level 94 has a lower so ket 96 which fits 88 and includesaconventional glass faced,.liouid filled chamber containing a small bubble that, when the device is level, seeks the highest point in the chamber and is visible from above.

In bisecting the intermaxil ary space an other operations determining the proper occlusion of the denture, it is useful to have a visible outline of a horizontal plane in this area. To form this outline, I attach upstanding p ns I00 to the arms of the articulator. as I0, H, by connecting arm-s I02. The three pins I00 are at the apices of a trian le which I graphically establish by snapping rubber band I04 or a thread therearound. This triangle lies in a horizontal are scored in like manner to provide grooves for reception ofthe band or thread.

I have found that with slight preparation of models I 4. I6 before mounting them in the articulator, the production of the dentures can be greatly facilitated. Each model has a flat'base face I I0 which is employed in mounting the same on the mounting p ates. By placing the model flat on base plate H2. as shown in Figure 4. andemploy ng the spiling means there disclosed I scribe thereon the spiling or guide ine H4. The spiling means comprises the upright gui e c lumn I20 on which is pivotally and slidably mounted in carria e I22 which has outstan ing fin er I24 and s rib n point I28. The smiling operat on is perf med by'rmtat n model M on base plate II 2 w th point I28 in onta t with the exposed face of the model and fin er I24 r ding on the crest or ridge representing in the model the upper boneline of t e patie t. It s important that point I26 be kept at ri ht an les to the ridge being traced'during the scribing of line I I4.

Steps in preparing denture After positioning upper bite-plate II! on b tetable I8 with median lines I1 and I fi'coinciding, as sho n in Fi ure 3, bite-plate I is engaged with the patient v maxilla. The d ntist. having first posit oned the patients head in a vert cal po it on, adr'sts spirit leve 2 one ay or the other through use of knob 34 until the bubble is centered. Transferring bite-table I8 to upsnugly-over the upper end of h ft 0 plane since the pins right column 46, the table is adjusted by means.

of knob 58 until the bubble in spirit level 26 again indicates that a horizontal position has been reached. At this point,,bite-plate I0 will havethe same lateral inclination zontal as it assumed While in position on the patients maxilla. Bite-plate I0, as shown in Figure 1, has been oriented to this position. Model I4 is then positioned on bite-plate I0 and will assume the same transverse plane as the patients maxilla. Model I4 is attached as by cement to the hinged and $0 by means of plaster-of-Paris I30 which. adheres to the flat face of the model and tends to regarding the horiexude through and mushroom over the edges.

of the openings or ports in mounting plate 90.

Bitetable It may then be removed and biteplate I2 be temporarily joined with bite-plate- I32 Which may be either utility wax,

ID by fillets or plaster as shown in Figure 2. Of course, the bite-plates will be locked together with their incisal portions in contact with the proper centric;

relationship established. Model I6 may thenrbe positioned in fitting relation with bite-plate I2.

In this H4 will be exposed to the dentist or as seen in Figure 2, even though th bite-plates conceal the ridges of the model from view. Lines iii serve as guides in the fore-and-aft tilting of the models in order that there may be adesired bisectioning of the intermaxillary space between the crests of the jaws as an aid in the correct placement of teeth in proper chewing and other mind that upper model M is first. only supported on plate and that the hinge; between plates the denture for 89 and 99 is still free, it willbe seen thatthe:

models and bite plate assembly can: be readily tilted about. a lateralaxis represented by hinge pin 92.

With the spiling lines zontal plane established H4 visible and the-horibyband or thread I04,

the technician views the ,articulatorfrom. the

side and proceeds to tilt plate 90'relative hinge pin 92 until he has bisected the interniaxillary space as he desires. He then as shown in. Figure 2 looks lower and around and between hinge. such as is shown in dottedlines inFigure'Z, can be placed under lower. model. Hi to support it when bite-plates I0 and I2 have. been removed.

Thepreparation of the denturesmay thereafter proceed according to custom.

By the use of the structures and techniquesthat have been described it is possibleto a nor'-= inally careful technically trained person to provide a patient with very comfortable artificial dentures that arefunctionally inter-related, are very perfect functionally for mastication and have high esthetic characteristics. Also itis possibl for the'dentist to-save much time in his work, to work with confidence that the outcome will be pleasing to the patient, and that he will not in the future have to devote much additional time to pacifying the patient or changing and;

or techniques ported mounting plate mounting arrangement, spiling lines technician,

functions. Bearing, in

upper mounting; plates 89. and 90 together by fusing additional plaster I40 them to immobilize the- Thereupon,.a lower mounting plate I 42,.

and, by their refiec-.

been -described certain details of' construction and operation andflspecific' methods; but it will be understood" that 7, changes and modifications may be made by those skilled in the art to meet particular circumstances. It is therefore intended that such modifications and alterations as fall within the spirit and scope of the subjoined claims shall likewise be covered by this patent.

Having thus described my invention, I claim:

1. In the preparation of dental prosthetic devices, the method, comprising: scribing on the sides of models of a patients maxilla and mandible lines corresponding to the profile of the ridges of the maxilla and mandible; forming a bite plate of the maxilla of the patient; placing said bite-plate in engagement with the patients maxilla and determining the plane of occlusion laterally oi the patients head; placing said bitcplate under the upper supporting member of an articulator in the same plane of occlusion laterally of said articulator as the plane of occlusion determined in contact with said maxilla; positioning a model of the patients maxilla on said maxilla bite-plate; pivotally connecting said maxilla model to said upper supporting member to pivot about a horizontal axis running transversely of said articulator forward of said model; securing a model of the patients mandible to said maxilla model with their incisal portions in contact in proper occlusal relationship; swinging said models about said horizontal axis until a position of desired division of intcrmaxiilary space has been reached by reference to said scribed maxilla and mandible ridge lines; and then securing said maxilla model fixedly to said upper supporting member by immobilizing the pivotal connection.

2. In the preparation of dental prosthetic devices, the method, comprising: forming a bite plate of the maxilla of the patient; placing said bite-plate in engagement with said maxilla and determining the plane of occlusion laterally of the patients head; placing said bite-plate under the upper supporting member of an articulator in the same plane of occlusion laterally of said articulator as the plane of occlusion determined in contact with said maxilla; positioning a model of the patients maxilla on said maxilla bite-plate; pivotally connecting said maxilla model to said upper supporting member to pivot about a horizontal axis running transversely of said articulator forward or" said model; securing the model of the patients mandible relative to said maxilla model with their incisal portions located in proper occlusal relationship; swinging said models about said axis until a position of proper rore-and-aft division of intermaxillary space has been reached; and then securing said maxilla model fixedly to said upper supporting member by immobilizing the pivotal connection. I

3. In the preparation of dental prosthetic devices, the method, comprising: scribing on the sides of models of a patients maxilla and mandible lines corresponding to the profile of the ridges of the maxilla and mandible; orienting the model of the patients maxilla under an upper supporting member of an articulator in the same plane of occlusion laterally of said articulator as the plane or occlusion of the patients maxilla laterally of the patients head; pivotally connecting said model to said upper supporting member to pivot about a horizontal axis running transversely of said articulator forward of the model; securing the model of the patients mandible to said maxilla model. with their incisal portions in contact in proper occlusal relationship; establishing a visible outline in a horizontal plane in the intermaxillary region; swinging said models about said axis until a position of desired division of intermaxillary space has been reached by reference to said scribed maxilla and mandible ridge lines and said visible outline; and then securing said maxilla model fixedly to said upper supporting member by immobilizing the pivotal connection.

4. In the preparation of dental prosthetic devices in which a model of the patients maxilla is to be positioned on an upper supporting member of an articulator, the method comprising: forming a bite-plate of the upper jaw of the patient and providing the same with a generally fiat lower exterior surface, disposing the patients head in a vertical position relative a vertical plane passing from front to back of the head, placing the bite-plate in the patients mouth on the maxilla and determining the lateral relation of the flat portion of the bite-plate to a true horizontal, supporting said bite-plate by said fiat surface and locating the bite-plate in the articulator adjacent an upper supporting member with the flat surface in the same lateral relation to the true horizontal as the flat surface of the bite-plate occupied in the patients mouth, whereby the model of the maxilla relating to said bite-plate may be placed in the bite-plate and attached to the upper supporting member in actual simulation of the lateral orientation of the patients maxilla.

5. In the preparation vices in which a model of a patients maxilla is to be joined to an upper supporting member of an articulator, the method comprising: placing a bite-plate on the maxilla, disposing the patients head in a vertical position relative a vertical plane passing from front to back of the head, determining the lateral relation of the bite-plate to true horizontal, locating said bite-plate in an tarticulator adjacent the upper supporting member thereof and in the same lateral relation to true horizontal as the bite-plate occupied in the patients mouth, positioning the model relating to said bite-plate in said bite-plate and beneath said upper supporting member of the articulator. and attaching said model to said upper supporting member of the articulator. I

6. In the preparation of dental prosthetic devices, the method, comprising: orienting a model of a patients maxilla member of an articulator in the same plane of occlusion laterally of said articulator as the plane of occlusion of patients maxilla laterally of the patients head; pivotally connecting said model to said upper supporting member to pivot about a horizontal axis running transversely of said articulator forward of the model; securing a model of the patients mandible to said model of the maxilla with their incisal portions associated in proper occlusal relationship; swinging said models about said axis until the position of desired division of intermaxillary space has been reached; and then securing said maxilla model fixedly to said upper supporting member.

DUNCAN S. McPHEE.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,581,914 Bonoff Apr. 20, 1926 1,830,248 Smith Nov. 3, 1931 2,001,963 Keller I. May 21, 1935 2,418,648 Kile Apr. 8, 1947.

of dental posthetic deunder an upper supporting 

